The present invention relates to the improvement in a heat pipe type heat-exchanger for ventilation, with which the exchanging work of connection ducts etc. for air-supply and air-discharge would be eliminated, even if the open air may be at any temperature to that inside the chamber to be ventilated.
The heat exchanger according to the invention is suitable as a ventilation device for the cultivation of mushrooms, in particular, making the exchange of connection ducts unnecessary in summer and in winter.
The prior art of heat-exchangers for ventilation will be explained taking the air-conditioned cultivating chamber for mushrooms as an example.
The important matters for the environment in the cultivating chamber for mushrooms are to lower the concentration of carbon dioxide gas and to maintain the chamber temperature constantly through the year. For these reasons, in the cultivating chamber for mushrooms, the heat-exchanger for ventilation is installed in many cases from a viewpoint of energy conservation. However, since the humidity is extremely high in the cultivating chamber for mushrooms, a large quantity of moisture adheres to elements of the heat-exchanger when discharging the air in the chamber and further, since the spores of mushroom floating in the chamber adhere to this deposit, the stabilized use for a long term becomes impossible, if the space between elements is small as in the case of the usual whole heat-exchanger.
The inconvenience as described above has been overcome by using the heat pipe type heat-exchanger in which the space between elements is widened to some extent. In this conventional heat pipe type heat-exchanger, a plurality of heat pipes are disposed vertically relative to the case and, connected with fins made of aluminum alloy, they are fitted in the case.
The inside of said case is divided into two chambers at the top and bottom. A fan is provided for the respective chambers and the side plates of the case are cut open in the direction of the flow passages of air by fans mounted in the structure. Moreover, since it is more efficient to allow the working fluid to move in a way that it evaporates at one end of the heat pipe in the lower chamber of the case and condenses at other end of the heat pipe in the upper chamber, the air is discharged through the lower chamber and supplied through the upper chamber to exchange the heat in winter when the air temperature is lower in the open air than in the cultivating chamber. Inversely, in summer when the air temperature is higher in the open air than in the cultivating chamber, the air is supplied through the lower chamber and discharged through the upper chamber to exchange the heat. For this reason, the power source wires are connected so that the rotating direction of the fans is reversed in summer and in winter, and the air-discharging and air-supplying ducts are reversed.
The conventional heat pipe type heat-exchanger for ventilation aforementioned is generally fitted to the side wall of the cultivating chamber for mushrooms and, in order to raise the efficiency of supply and discharge of air, ducts are usually connected. The method of connecting ducts is as follows:
In winter, as shown in FIG. 3, one opening of the outdoor air supplying duct (d') is connected to the upper chamber (12) of the heat-exchanger (4') and the other opening is left open extending upward. Also, one opening of the indoor air-supplying duct (b') is connected similarly to the upper chamber (12) and the other opening extends sideways so as to be open to the upper portion of the cultivating chamber, so as to supply the air uniformly to the chamber. Next, one opening of the indoor air-discharging duct (a') is connected to the lower chamber (13) of heat-exchanger (4') and the other opening is open to the lower portion of the cultivating chamber in order to discharge carbon dioxide gas stagnating at the bottom of the cultivating chamber. Further, one opening of the outdoor air-discharging duct (c') is connected similarly to the lower chamber (13) and the other opening is left open extending downward to separate it from the opening of the outdoor air supplying duct (d').
Further, is summer, since the movement of supply and discharge of air in the top and bottom chambers of the heat pipe type heat-exchanger for ventilation reverses from that in winter, the alteration of the connection of power source wires in necessary to reverse the rotation of each fan and the connection of ducts for air-supply and air-discharge to the heat-exchanger must be exchanged between the top and bottom chambers, resulting in the inconvenience of handling.
Moreover, since the power source wires of two fan motors of such heat-exchanger are usually connected to the external power source wire inside the heat-exchanger, they are exposed to the atmosphere of high humidity in either season of summer and winter. This can cause an accidental short circuit. Furthermore, since the reversing changeover switch of the fan motors is generally placed in the environment of high humidity, a short circuit here is also apt to occur.
As a result of extensive investigations in view of this situation, the inventors have known that, since the working fluid moves in either direction of right and left in equal efficiency if using the heat pipe installed horizontally relative to the case, it is immaterial which end of the heat pipe may be made the evaporation section (or the condensation section). And, in consequence of further investigations, a heat pipe type heat-exchanger for ventilation has been developed according to the invention, wherein the rotating direction of fans is made constant whatever the temperature of the open air may be, for example, through the seasons of summer and winter and yet the exchange of ducts is unnecessary.